The approval of Biogen Idec’s MS therapy Tecfidera follows months of breathless Wall Street hype, and it looks like doctors are psyched for the drug, too. In a MedLIVE PULSE survey conducted by WorldOne Interactive, 40% of U.S neurologists polled said they’re currently warehousing patients in anticipation of the new multiple sclerosis drug.

Tecfidera faces competition from Sanofi’s Aubagio and Novartis’ Gilenya, but the Biogen Idec drug comes to the market with some advantages. Gilenya boasts a similar efficacy profile but carries cardiovascular risks, while Aubagio has been plagued with efficacy questions.Two-thirds of physicians told WorldOne Interactive that the availability of Tecfidera would make them less likely to prescribe Aubagio, and 68% said the same about Gilenya. One neurologist noted: “Starting patients on Tecfidera is so easy compared to Gilenya. Why use Gilenya given this new medication?”

While they may be less likely to prescribe other treatments with Tecfidera approved, that’s not to say they’ve written them off completely. Four-fifths of doctors polled still believe Aubagio has a place in the pharmacopeia, while 84% believe Gilenya should remain in the neurologist’s repertoire, because “some patients can be good candidates for Gilenya,” and “alternative treatment options should be made available.”

Either way, both the Sanofi and Novartis products would seem to be in danger of becoming the alternative and not the go-to treatment.

Some estimates say Tecfidera might generate $3.25 billion and corner one-fifth of the market initially, and as much as $6 billion by 2020. It’s expected to be a safer and more effective treatment than other oral therapies, and it’s indicated for the most common form of MS (relapsing-remitting multiple sclerorsis or RRMS). In clinical trials, it reduced relapse rates by up to 43%.